Rapid diagnostic tests allow one to detect the presence of antibody, antigen, metabolite toxin or other substance in a sample. Common applications include diagnosing diseases and detecting drugs, biological entities or harmful agents. In addition to being accurate, the tests are preferably easy to use, self-contained and user-friendly without requiring expensive laboratory instruments or training. Currently available tests lack sensitivity or require expensive laboratory equipment thus requiring improvement.
Presently available rapid diagnostic tests often use a colored particle, dye or enzymatic color-producing reaction to generate a visible test result. Such tests are often unsuitable for detecting low levels of a target analyte. Other diagnostics use fluorescence. However, fluorescent tests are laboratory based because the fluorochromes used in them have small stokes shifts which require sophisticated and expensive instruments to analyze the emission light. These tests use time-resolved fluorescence to obtain quantitative results.
The present invention uses fluorochromes with a large stokes shift. This eliminates the need for laboratory instruments to differentiate the excitation from emission light. The test system greatly enhances the detection level of counterpart color-developing systems, provides a concise result and can be inexpensively produced.